Turbulent vertical heat flux under Antarctic on-shelf sea ice intensified by the Amundsen Sea Undercurrent

Wang, Xingchi ORCID: https://orcid.org/0000-0002-0401-4915; Silvano, Alessandro ORCID: https://orcid.org/0000-0002-6441-1496; Firing, Yvonne ORCID: https://orcid.org/0000-0002-3640-3974; Fernández Castro, Bieito ORCID: https://orcid.org/0000-0001-7797-854X; Spingys, Carl P.; Dotto, Tiago S. ORCID: https://orcid.org/0000-0003-0565-6941; Clement, Louis ORCID: https://orcid.org/0000-0002-6935-9455; Holland, Paul R. ORCID: https://orcid.org/0000-0001-8370-289X; Naveira Garabato, Alberto C.. 2025 Turbulent vertical heat flux under Antarctic on-shelf sea ice intensified by the Amundsen Sea Undercurrent. Communications Earth & Environment, 6, 613. 12, pp. 10.1038/s43247-025-02598-2

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Official URL: https://doi.org/10.1038/s43247-025-02598-2

Abstract/Summary

The Amundsen Sea Undercurrent, off West Antarctica, transports warm Circumpolar Deep Water onto the continental shelf, driving basal melting when it reaches the ice shelves through troughs. However, vertical heat loss from the warm inflow to the cold upper ocean remains understudied. Here we use observations and numerical modeling to investigate mixing-induced vertical heat flux in a major trough, finding: (1) turbulent mixing transfers 1.7 W m −2 of heat to the upper ocean during observational period, potentially reducing sea ice growth by 0.2 m yr −1 ; and (2) mixing is modulated by undercurrent strength, with stronger undercurrent enhancing vertical shear across the on-shelf thermocline, promoting internal wave breaking and mixing. This flux is non-negligible in the on-shelf heat budget, particularly on annual and longer timescales. Our findings highlight the occurrence of vertical heat exchange over the Amundsen Sea shelf and indicate its potential role in modulating sea ice and ice-shelf melting.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1038/s43247-025-02598-2
ISSN:	2662-4435
NORA Subject Terms:	Marine Sciences
Date made live:	04 Aug 2025 14:36 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/540002

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1038/s43247-025-02598-2

ISSN:

2662-4435

NORA Subject Terms:

Marine Sciences

Date made live:

04 Aug 2025 14:36 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/540002